Measuring Urban Expansion

This report presents a technical overview of urban form and land-use measures that can be used to describe large-scale expansion and change in the built environments of metropolitan areas. The metrics it includes have been developed in conjunction with the World Bank’s work on quantifying urban expansion and transformation in the East-Asia and Pacific regions, but similar measures can be adopted for tracking spatial change in metropolitan areas around the world.

The measures discussed focus primarily on capturing the spatial characteristics of urban form and land-use distribution – qualities of metropolitan areas that can be detected from rather basic remote sensing imagery and that can be readily operationalized in a large number of cities.

The work builds upon numerous previous research initiatives that have studied qualities of metropolitan form. We also propose a few new metrics that have not been widely operationalized in studies of metropolitan growth patterns in the past. Our aim has been to evaluate existing measures and to propose improvements that capture more nuanced and more useful aspects of metropolitan form.

Measures of metropolitan form are most useful, however, if they can be coupled with other types of data about each city – their economic indicators, social and demographics indicators, transportation surveys, and environmental performance metrics. We do not discuss these latter kinds of data in depth, but emphasize how form and land-use characteristics relate to some of these factors.